1. Field of the Invention
The present invention relates to a system for exchanging almost exhausted roving bobbins with full packaged roving bobbins in a ring spinning frame.
2. Description of the Related Art
Several methods of carrying out an exchange of almost exhausted roving bobbins with full packaged roving bobbins applied to the conventional ring spinning frame have been proposed. For example, Unexamined Japanese Patent Publication Sho 50(1975)-76341 discloses such a method. (Hereinafter referred to as a first method). To carry out the first method of exchanging roving bobbins in the conventional ring spinning frame, a transporting pallet provided with a plurality of bobbin hangers arranged in twin parallel alignments is displaceably mounted on a transporting rail disposed at a creel position of the ring spinning frame. In this first method, first, full packaged roving bobbins are held by the bobbin hanger of the transporting pallet, and the spinning operation of the ring spinning frame provided with a plurality of draft units is started by feeding rovings from the respective full packaged roving bobbins of the transporting pallets which have been positioned at the creel position of the ring spinning frame. Then when the roving bobbins reach an exhausted condition, the driving of the ring spinning frame is stopped, then the another transporting pallet provided with full packaged roving bobbins is introduced onto the transporting rail at the creel position, and after discharging the transporting pallet holding exhausted roving bobbins from the transporting rail at the creel position, the rovings from the full packaged roving bobbins are then introduced to the corresponding draft units, and the spinning operation is started again.
The Japanese Examined Patent Publication Sho 60(1985)-14848 discloses another method of carrying out the roving bobbin exchange operation which is applied to the conventional ring spinning frame. This method is hereinafter referred to as the second method. In the invention disclosed by the above-mentioned publication, to carry out the second method of exchanging the roving bobbins, a transportation rail is arranged at a position outside the twin parallel alignment of bobbin hangers which was arranged at the creel position of the spinning frame, at both sides thereof, and a bobbin carriage provided with a plurality of bobbin hangers, to a number which is not less than the number of bobbin hangers of the above-mentioned twin alignments of the bobbin hangers, is displaceably mounted on the transportation rail. In this method, the spinning operation of the ring spinning frame is started when half exhausted rovings are held by the bobbin hangers of the back side (inside) alignments of the bobbin hangers and full packaged roving bobbins are held by the bobbin hangers of the front side (outside) alignments of the bobbin hangers, in a condition such that a taper effect is obtained between the above-mentioned twin alignments of bobbin hangers, and when the half exhausted roving bobbins reach an almost exhausted condition, while the full packaged roving bobbins reach an almost half exhausted condition, the almost exhausted roving bobbins are exchanged with the full packaged roving bobbins of the bobbin carriage, while rovings from the respective almost exhausted roving bobbins are severed so that free ends of rovings to be feed to the respective draft units of the roving frame are created, and these free ends of the respective rovings are pieced with the corresponding free ends of rovings from the respective full packaged roving bobbins. Immediately after or before this operation of exchanging roving bobbins, the bobbin hangers positioned in the front side alignment are exchanged with the bobbin hangers positioned in the backside alignment. As mentioned above, in this method, the roving bobbin exchange operation is carried out between one of the twin alignments of the bobbin hangers with the bobbin hangers on the bobbin carriage.
Japanese Unexamined Patent Publication Sho 63(1988)-256728 disclosed another method of exchanging the roving bobbins applied to the conventional ring spinning frame. This type of method of carrying out the roving bobbin exchange operation is hereinafter referred to as the third method. In the third method, each side of a spinning frame is provided with at least three creel positions, each creel position is capable of supporting a member provided with a plurality of bobbin hangers in alignment. For a better understanding of the third method, the embodiment disclosed in the specification of this invention is hereinafter explained. Each member can be transported between a roving room and a spinning room, and any combination of two creel positions are always occupied by the above-mentioned member holding roving bobbins for supplying rovings to the respective draft units, in such a way that the rovings from the roving bobbins of one of the above-mentioned two members are supplied to the corresponding draft units, which are alternate draft units from one end of the arrangement of the draft units, while the rovings from the roving bobbins held by the other one of the above-mentioned two members are supplied to the respective draft units, which are the draft units other than the above-mentioned draft units of the identical side of the spinning frame. In other words, the first and second members supply rovings to half of the draft units of the one side of the spinning frame, alternately. Regarding the other creel position which can be any one of the above-mentioned three creel positions, the above-mentioned combination of two members is maintained in a condition to receive a member holding a number of full packaged roving bobbins which is identical to the number of first and second members. To carry out the third method of exchanging roving bobbins, the first member held roving bobbins having a smaller size than the roving bobbins held by the second member, whereby a taper effect is applied between the above-mentioned two members. During the spinning operation, when the roving bobbins having the smaller size reach an almost exhausted condition, the rovings from the almost exhausted roving bobbins are severed so that a free end is created of each roving being fed to the corresponding one of the draft units, and then the above-mentioned free end of each roving is pieced with an end of a roving from the corresponding one of the full packaged roving bobbins held by the third member. Therefore, in the third method, the roving bobbin exchange operation is carried out between either one of the above-mentioned two members and the above-mentioned third member, without stopping the spinning operation.
As explained in the first-mentioned prior art, the method and apparatus for transporting the bobbin carriage along the overhead transporting rail is well known in the prior art. Besides the disclosure of the first-mentioned prior art, in the disclosure of Japanese Examined Patent Publication Sho 63(1988)-29016 and Japanese Unexamined Patent Publication Sho 62(1987)-263332, a battery car is utilized to displace the bobbin carriage along the transporting rail, and thus provide useful technical information as to the state of the art at the time of the present invention.
In the experience of the present inventors, the above-mentioned three methods for exchanging roving bobbins have respective problems which should be solved.
Namely, the first method has an advantage such that the almost exhausted roving bobbins of twin alignments arranged at the creel position can be exchanged with the full packaged roving bobbins at one time, but a drawback arises in that the above-mentioned roving bobbin exchange operation must be carried out after stopping the driving of the spinning frame, and thus the productivity of the ring spinning frame is lowered.
The second method has an advantage such that the roving bobbin exchange operation can be carried out without stopping the driving of the roving frame. Nevertheless, it is necessary to use an apparatus for exchanging the exhausted roving bobbins with the full packaged roving bobbins and an apparatus for exchanging the relative position of the front side alignment of the bobbin hangers and the back side alignment of the roving bobbins, and accordingly, an increase of the installation cost for these apparatuses is inevitable. Moreover, in this method, it is essential to position the roving bobbins in a tapered arrangement between the twin alignments of roving bobbins at the creel position, and therefore, when it is necessary to change the kind of yarns produced by the spinning frame, the preparation of roving bobbins on these bobbin hangers becomes difficult, and further, if various kinds of yarn on a small production scale are to be produced, the above-mentioned problem becomes serious.
On the other hand, the third method, has an advantage in that the roving bobbin exchange operation can be carried out without stopping the driving of the spinning frame, but since the tapered arrangement of the roving bobbins between at least twin alignments of bobbin hangers is essential, the problem arising when the kind of yarn to be produced is changed, which is similar to the problem of the second method mentioned above, still remains.